While violence in Iraq may squeeze drivers' wallets this summer, the U.S. is headed for a gas glut over the next few years as demand slows.

"Tightening fuel efficiency standards for automobiles, and changing consumer preferences look set to send U.S. gasoline demand back on the declining course on which it embarked in 2007," the Paris-based agency said in its latest forecast published Tuesday.

U.S. demand for gas alone accounts for about 10% of world oil consumption, and the decline will coincide with more ample supply, according to the IEA.

The U.S. energy boom is boosting output of oil that is rich in gasoline at a time when refineries are under pressure to produce more diesel and jet fuel amid an increase in industrial activity and air travel.

But the refineries still have to sell the gas produced from processing each barrel, and will be looking for markets to soak up that surplus.